The HIV epidemic in the United States most severely affects men who have sex with men (MSM): 57% of all new infections occur in this population. Black MSM bear a disproportionate burden, with prevalence of 28%, in contrast to 19% in MSM overall. Black MSM undergo HIV testing less frequently than other MSM; are less likely to be aware that they are HIV infected; are more likely to experience delays in entry into HIV care; and are less likely to be prescribed ART when eligible. These disparities are pronounced in substance using MSM, as substance users are at elevated risk of late diagnosis and delayed engagement in HIV care. The combination of pervasive stigma associated with MSM behavior and high rates of substance use hinders effective prevention efforts in this population, even as the prevalence of infection in Black MSM in some US cities approaches 50%. Reducing HIV-related disparities in MSM and among Black Americans are National HIV/AIDS Strategy priorities and are essential to the effort to control and prevent HIV/AIDS in the US. Setting: The study will seek and recruit substance-using Black MSM in New York City for HIV testing and will link and retain those who are HIV-infected in HIV primary care. Study Aims: In response to the urgent public health need to seek substance-using Black MSM, identify those with HIV infection, and link the latter to HIV services, the study aims are as follows: Seek and Test: Respondent driven sampling (RDS) will be used to recruit substance-using Black MSM for HIV testing. RDS has been used in HIV surveillance among hard-to-reach populations and, to a limited extent, as a strategy for engaging hard-to-reach populations in services. We will assess the feasibility and effectiveness of using RDS to seek, recruit, and offer HIV testing to this high-risk population. Link and Retain: Participants with reactive rapid HIV test results and who are not currently in care will be randomized to two linkage and retention strategies: patient navigation (PN) and financial incentives (FI). One hundred participants will be randomized into each arm of the study. The primary objectives are: 1) to assess the feasibility and effectiveness of using RDS for seeking and recruiting substance-using Black MSM at high risk for HIV acquisition for rapid HIV counseling and testing; 2) to assess the feasibility and effectiveness of using two interventions, PN and FI, for linkage and retention in HIV care; and 3) to assess the cost-effectiveness of PN and FI for linkage and retention in HIV care. This study has the potential to identify effective methods to seek and test substance-using Black MSM, to link the HIV infected to services, and to retain them in care and treatment. The success of such an effort responds to priorities with the national HIV strategy. Results will inform innovative approaches to engaging highest-risk, difficult-to-reach individuals in HIV counseling and testing and retaining them in care and treatment.